2025年7月1日

Flysch rock formations, Zumaia, Basque Country, Spain

Looking like layers of lasagna as they're exposed by the tide, these wavy formations were snapped not in Italy but on the northern coast of Spain. This distinctive pattern of shallow rocky ridges, known as flysch, arose during a process called orogeny: the birth of mountains. As tectonic plates smashed together and were thrust upward to form the Basque Country's coastal peaks, landslides crashed down the new slopes and created powerful currents when they entered the water. Sediment was compressed against the seafloor by these currents, resulting in rigid strips of rock that deformed into undulating shapes as the fault settled.